Ligating clip appliers or applicators have become quite common in the operating room. These appliers are generally able to engage a ligating clip between a pair of opposed jaws. Thereafter, the jaws crush the clip by applying a lateral pressure thereto. The clip is placed around a blood vessel to occlude or ligate the vessel, or alternately, the clip may be used to approximate severed tissue. Clip appliers may engage and clamp a single clip (and thereafter be reloaded), apply multiple clips simultaneously, or multiple clips seriatim, from a stack of clips held in a clip magazine on the clip applier. Exemplary clip appliers of each type are disclosed in an Information Disclosure Statement filed herewith.
Certain clip appliers which may be considered "automatic" are disclosed in the art, and for purposes of distinguishing with the invention claimed in this application, are discussed herein. Each of these devices has a pusher bar (for loading clips) and a camming channel (for closing clips) which move in opposite directions of one another, in order to provide more efficient clip closure and loading between the jaws. For instance, Deniega, U.S. Pat. No. 4,598,711 presents a clip applying device wherein a mechanism for loading clips is moved proximally while a separate mechanism for closing clips is moved distally, to close a clip between a pair of jaws. Then, these motions are reversed, in order to load a new clip between the pair of jaws. But, in Deniega, there are certain perceived drawbacks. First, the respective loading and closing mechanisms are operated in conjunction with a series of links and gears. These mechanisms require precise interaction of moving members, and are perceived as relatively cumbersome to operate properly. Second, a single tension spring controls the mechanism, to reverse the motion of the loading and closing operations, but this spring is attached to the housing of the device. In contrast, it would be desirable to employ an improved spring system which would not require special attachment to, or interaction with, the housing. Such a design could be more easily manufactured. Further, it would be advantageous to provide such improved spring system that could be operated more easily, more quickly, and more reliably.
Alternately, another mechanism which functions quite similarly to the Deniega patent is described in Green et al., U.S. Pat. Nos. 5,030,226 and 5,197,970. Here, the pusher bar (for loading clips) and camming assembly (for closing the jaws) are controlled not by one tension spring, but by a series of compression springs. Moreover, there are a pair of lever links attaching the pusher bar to the handles which operate the device. Also, the lever links slide within the handle of the device. Both the existence of the compression springs and the multiple lever links result in a device which necessarily requires a great deal of mechanical force to activate, as well as an offsetting movement resulting from the use of multiple lever links. Consequently, much energy must be used to overcome the friction resulting from the operation of the multiple links and the multiple compression springs. In addition, further amounts of energy are required to guide the pusher bar assembly, as it is connected to a pair of guide pins which are conducted through a pair of guiding channels located in the handles of the device. Again, the resultant energy and frictional losses create a device which is less than optimally efficient.
Furthermore, the Green device presents a mechanism which requires a certain amount of lost motion to be overcome in order to time and coordinate the motion of the pusher bar and the jaw camming assembly. In other words, there is no direct coordinated translation between motion of the handles to activate the device and motion of the pusher bar and jaw camming assemblies. This resultant lost motion requires yet additional force to be expended (over a resultantly lengthened period of activation time) in contrast to what would be considered an optional device.
Yet another "automatic" device are those endoscopic clip applying mechanisms described in Stefanchik et al. U.S. Pat. Nos. 5,171,249 and Hughett et al., 5,171,247. There, one tension spring activates the entire mechanism. Also, the spring is connected between the pusher bar and camming assemblies, and not between one assembly and the handle, as in the aforementioned Deniega and Green patents. This connection and the interaction of the two assemblies removes any lost motion from the operation of the device. Further, the clip appliers described in the Stefanchik et al. and Hughett et al. patents employ a single trigger actuator which is directly connected to the jaw closure mechanism and which is connected through a single, pivotably mounted link to the pusher bar mechanism. A special guide channel is provided in the body handle for guiding one end of the link as it moves the pusher bar mechanism proximally during operation of the trigger. Because this could result in added frictional losses in the system, it would be desirable to provide an improved system with less friction loss and with a less complex component design.
Finally, the clip appliers disclosed in the Stefanchik et al. and Hughett et al. patents are specially designed for use in endoscopic surgery with single trigger action wherein the trigger is directly connected to the jaw closure channel mechanism. This is highly effective and desirable in endoscopic procedures. However, in some applications, particularly in some types of open surgery procedures, a surgeon may prefer to employ a clip applier having a pair of handles. Indeed, in such applications it would be desirable to provide a clip applier with a pair of handles for operating the jaw closure mechanism through an appropriate linkage system to provide the surgeon with the feel of a traditional scissors type action.
Heretofore, there also have been certain other perceived drawbacks noted in conventional, "open" procedure multiple clip applying mechanisms. First, the jaws of the clip applier are traditionally positioned on and angled toward the same side as the magazine of clips with respect to a central dividing plane which lies along the longitudinal axis defining the shaft of the ligating clip applier. This has resulted in the clips necessarily being fed into jaws from the "underside" of the jaws, as the jaws of such clip applier are generally configured to angle in a direction apart from the dividing plane but toward the magazine of clips.
Second, the jaws of previous clip appliers have been configured so that they approximate and clamp the clip. There has been no emphasis on the method of jaw/clip closure. That is, heretofore, all the previous methods of jaw closure have relied on mere approximation of the jaws. Until now there has not been a careful designing of the jaws and the manner in which they approximate clips so that there is first a distal closure of the jaw legs, and then a gentle proximally moving closure of these jaw legs, so that the jaw closing force is concentrated on different points on the clip as the jaws flex and roll over the clip, so that the included distal angle of the clip legs at the crown of the clips is substantially 0.degree..
Third, the locking mechanisms which provide a locking of the jaw approximating mechanism have been simple barrier devices, but, at the same time, have been bulky in size with respect to the jaw approximating device itself. There has not been improvement of the lockout mechanism in size or performance capabilities.